Stewart 



The Tree as an Invention 



points will disclose but a hundred, or 

 fifty, or forty. The rings become fewer 

 and fewer. 



If we take a particular ring and fol- 

 low it up we find that it grows smaller 

 and smaller till it diminishes to a point, 

 a ring near the centre of the stump 

 coming to an end at no great distance 

 from the ground, while one a greater 

 distance from the centre reaches to a 

 correspondingly greater height. And 

 each of these rings, according as it is 

 the fortieth or fiftieth or hundredth 

 from the centre, will show the height, 

 as well as the thickness that the tree 

 has attained in that number of years. 

 As anyone can see by its mere outer 

 form, a tree grows smaller upward, 

 tapering from a considerable girth at 

 its base to a fine point at its extrem- 

 ities. And when we examine these inner 

 sheaths of annual growth we find that 

 they do the same. 



Thus we see what a tree really is. It 

 is a sheath of life spread over the dead 

 trees of other years. Generation stands 

 within generation, successively wrapped 

 about. The outer life of cambium and 

 leaf and bud uses this as a trellis to go 

 up and reach out sunward and skyward. 

 Instead of throwing its old skeleton 

 aside each year and starting anew, it 

 clings to its dead bones, profits by their 

 stature, and makes tubes in them to 

 provide the supply of water for a larger 

 and more ambitious growth. When we 

 compare this way of growth with other 

 methods, both animal and vegetable, 

 it must strike us as a most interesting 

 invention. 



As the inner or lifeless part of a 

 tree is incapable of growth or upward 

 expansion, a nail driven into a young 

 tree at any particular height will re- 

 main at that distance from the ground 

 throughout the life of the tree. And a 

 branch coming out at any point will 

 not be carried upward as time goes on. 

 In the giant sequoia of California 

 we have trees whose long life is a 



173 



matter of constant marvel. But the 

 part of them that is really alive is of 

 quite recent growth. A sequoia may be 

 three or four thousand years old, and 

 an oak or elm three or four hundred, 

 provided the inner part, which was ac- 

 tually in existence that long ago, is not 

 rotted away and represented by mere 

 space. 



II 



In the essential matter of life and 

 death, a tree presents two great points 

 of difference from an animal. An ani- 

 mal is alive all the way through, even 

 its bones, tendons, and cartilaginous 

 parts containing live cells which are en- 

 gaged in the work of upkeep and re- 

 pair. As we have seen, a large tree is not 

 alive all the way through, the bulk of 

 its body being all skeleton and dead. 

 But when we consider the live tissue 

 that its skeleton supports, we find that 

 the tree offers a different sort of con- 

 trast. An animal grows rapidly at first. 

 It has an exultant original cell which 

 contains the whole beginning, meas- 

 ures but .004 of a cubic centimetre. By 

 the time the child is born, it has in- 

 creased—by one of those biological 

 feats of geometrical progression— to a 

 billion times that size. Here nature 

 steps in with inhibiting hand, and the 

 life processes begin to slow up, so that, 

 from his babyhood to his twentieth 

 year, a man has increased but sixteen 

 times. At this point all growth stops, 

 and the vitality steadily declines until 

 finally the forces of life and death are 

 just about balancing one another and 

 the machine may stop in an instant. 



Take note of a tree and consider 

 how different all this can be. A tree 

 never loses the vital power of growing. 

 It starts out as rapidly, retains the 

 power of geometrical progression, and 

 is ever young. There seems to be no 

 reason in itself why a tree should not 

 live forever. Tlie aged man, looking up 



